package cn.micai.base.thread;

/**
 * 描述：双重检查
 * <p>
 *
 * @author: 赵新国
 * @date: 2018/2/22 15:13
 */
public class DubbleSingleton {

    private static DubbleSingleton ds;

    public static DubbleSingleton getDs(){
        if (ds == null) {
            try {
                // 模拟初始化对象的准备时间...
                Thread.sleep(3000);
            } catch (Exception e) {
                e.printStackTrace();
            }
            synchronized (DubbleSingleton.class) {
                if (ds == null) {
                    ds = new DubbleSingleton();
                }
            }
        }
        return ds;
    }

    public static void main(String [] args) {
        Thread t1 = new Thread(new Runnable() {
            @Override
            public void run() {
                System.out.println(DubbleSingleton.getDs().hashCode());
            }
        },"t1");

        Thread t2 = new Thread(new Runnable() {
            @Override
            public void run() {
                System.out.println(DubbleSingleton.getDs().hashCode());
            }
        },"t2");

        Thread t3 = new Thread(new Runnable() {
            @Override
            public void run() {
                System.out.println(DubbleSingleton.getDs().hashCode());
            }
        },"t3");

        t1.start();
        t2.start();
        t3.start();

    }
}
